Obon is a fun opportunity to spend time with family and relatives.
On the other hand, for babies and young children, this is a time when factors that can cause them to get sick tend to accumulate, such as long-distance travel in the midsummer heat, unfamiliar food, bedding stored for long periods, and environments with dogs or cats.
Especially for infants and young children, it is difficult for them to communicate that they are hot or feeling unwell.
Before returning home, let's confirm transportation, meals, bedding, and allergy medication.

[For Guardians] Things to Check Before Returning Home

☀️ Summer heat protection for babies and young children

Children's thermoregulation is not fully developed, making them susceptible to heat and dehydration.
While on the move, please try to maintain a cool environment and stay hydrated.
For babies who are drinking breast milk or formula, pay attention to feeding intervals and how they drink more than usual.
For babies who are progressing with solid foods, gradually offer small amounts of water or barley tea, according to their age and usual drinking habits.
Choose lightweight, breathable clothing.
Avoid direct sunlight
If possible, move during the relatively cooler times of the morning or evening.
Check complexion, sweat, mood, and urination frequency while moving.
Use air conditioning appropriately inside vehicles and rooms.
If symptoms such as lethargy, slow reaction, pale complexion, inability to drink fluids, or extremely low urine output are present, move to a cool place immediately.
If someone is disoriented, unresponsive to calls, having seizures, or unable to drink fluids on their own, they require emergency medical attention.

When traveling by car

In the summer, car interiors can reach dangerously high temperatures in a short amount of time.
Never leave a baby or child alone in a car with the engine off.
For long-distance travel, take a break every 1-2 hours to hydrate, change diapers, and check on your child's condition.
Please use the child seat correctly according to your child's age, physique, and the product's instruction manual.

When traveling by airplane

During airplane takeoffs and landings, changes in air pressure can cause ear pain.
Encouraging sucking and swallowing actions, such as breastfeeding, bottle-feeding, or using a pacifier, can help with ear pressure regulation.
Symptoms in the ears tend to occur particularly during descent before landing, so be prepared for things like breastfeeding.
Do not self-medicate with over-the-counter antihistamines or cold medicines to prevent ear pain or to induce sleep.

When traveling by train or public transportation

During peak seasons, the opportunities to come into contact with infectious diseases also increase.
Let's make sure to wash our hands when we get home and before we eat.
If you have a fever, recurrent vomiting, or diarrhea, it is also important not to force yourself to move.

Please do not feed new foods to them while they are visiting home.

When visiting home, grandparents and relatives may offer you dishes and sweets that you don't usually eat.
Avoid feeding your child unfamiliar foods for the first time while visiting relatives.
It's okay if it's just a little.
"I'm big enough now, so it's okay."
I cannot make that judgment.
Food allergies can occur with foods children have never eaten before, even if they have never had symptoms previously.
Please try new ingredients at home in small quantities on a day when the following conditions are met.
When you visit your hometown, do not try new foods, regardless of your age.

Please be aware of tree nuts such as walnuts and cashews.

In recent years, food allergies and anaphylaxis caused by tree nuts, including walnuts, have been increasing in Japan.
Nuts and seeds are rarely consumed during infancy and early childhood, and some children may not try them until they are school-aged or older. Even children who have never had food allergies before need to be cautious.
When visiting family, the following foods may contain tree nuts:
Mixed nuts
Baked goods with walnuts and almonds
Chocolate
Bread and cake
Nut paste and nut cream
Dishes and sauces using nuts
When eating walnuts, peanuts, cashews, almonds, etc. for the first time, try them at home in small amounts rather than at your family home when visiting for the holidays.
Also, hard beans and whole nuts pose a risk of choking and aspiration, apart from food allergies.
Do not give hard beans or whole nuts to children 5 years old or younger.

🚑 Symptoms to watch out for after eating

Symptoms of food allergies often appear within a few minutes to about 2 hours after eating.
Please watch out for the following symptoms.
Hives, redness, itching
Swelling of the eyelids or lips
🔸Repeated vomiting
🔸Severe abdominal pain
Coughing, wheezing, having trouble breathing
Hoarse voice
Looking pale
Suddenly becoming limp and exhausted
If multiple moderate or severe symptoms appear, such as swelling of the face, lips, or throat, difficulty breathing, hoarseness, repeated vomiting, or lethargy with poor responsiveness, it may be anaphylaxis.
In such cases, please call 119 immediately.
Children who are prescribed EpiPen® or NEOFEY® should definitely carry them even while visiting their hometown, and make sure to check the usage instructions and expiration date in advance.

🛏️ For children with dust mite allergies, please prepare their bedding in advance.

In children with allergic rhinitis, asthma, or atopic dermatitis caused by dust mite allergies, symptoms can sometimes be aggravated by the bedding at their destination when visiting family.
Allergens contained in dust mite carcasses and feces accumulate in futons, mattresses, and pillows.
Futons that have been stored in a closet or similar place for a long time may contain large amounts of dust mite allergens.
If you experience the following symptoms every time you return to your parents' home, the bedding may be the cause.
Runny nose and sneezing increase when getting into futon
Coughing at night or early in the morning
🔸 Itchy eyes or skin
Asthma symptoms worsen

☀️ Sun-drying cannot remove dust mite allergens

Sun-drying does not remove allergens such as dust mite carcasses and feces that have accumulated in futons.
When airing out or beating futons, allergens can be stirred up into the air.

🧺 Please wash the futon thoroughly.

Please prepare one of the following at your hometown.
🔸Futons thoroughly washed via futon cleaning
🔸Properly cleaned and maintained rental futons
🔸Clean bedding used daily
Please use freshly laundered sheets and pillowcases as well.
Anti-mite sheets and anti-mite covers alone have no effect on improving symptoms.
For the bedding at your destination, please use freshly laundered futons or properly cleaned and maintained rental futons.

💊 Please continue taking your medications for dust mite allergies and asthma.

Even while visiting your hometown, please continue using your regular antihistamines, nasal sprays, inhalers, and other medications exactly as directed by your doctor.
Children with asthma should bring not only their daily medication, but also their inhaler to be used during an asthma attack.
In the following cases, please consult your regular doctor before returning to your hometown.
🔸Every year, when I return to my hometown, my cough and nasal symptoms get worse.
🔸I had an asthma attack recently
Coughs at night or during exercise are increasing
I am anxious about how to respond during a seizure.
Be sure to check in advance for holiday clinics and emergency medical facilities near your destination.

🐶🐱 Countermeasures for children with dog and cat allergies

There is absolutely nothing wrong with owning dogs or cats in itself.
However,While keeping dogs and cats,For children with dog and cat allergiesIt is difficult to create a home environment free from the effects of allergens.The medical limitations of living in the same environment with dogs and cats for people with dog and cat allergies.
Dog and cat allergens are not only present in their fur.
Fine particles originating from saliva, sebum, dandruff, and the like are spread throughout the entire house, including the air, floors, carpets, sofas, curtains, bedding, and clothing.
Therefore, in homes where dogs and cats normally live, allergens are present even in rooms where the animals do not enter.

🚪 Even if you put dogs or cats in another room, exposure to allergens cannot be avoided.

Methods like this cannot eliminate exposure to dog and cat allergens.
🔸Move dogs and cats to another room
Keep children and pets in separate rooms
Keeping children from touching pets
🔸Do not let dogs or cats into the bedroom
Clean before the stay
Use an air purifier
Wash dogs and cats before the stay

💊 If you experience symptoms every year, please see a doctor before returning home.

If you experience itchy eyes, a runny nose, sneezing, coughing, wheezing, or skin symptoms every time you visit a home with dogs or cats, please consult your family doctor before returning home for the holidays. While medication cannot eliminate exposure to dog and cat allergens themselves, it can help relieve your symptoms.
The medications used include antihistamines, antihistamine eye drops, steroid nasal sprays, and asthma inhalers.
The necessary medication, when to start using it, and the dosage depend on your child's age and symptoms. Do not use over-the-counter medicine based on your own judgment; please follow your doctor's instructions.

🧳 Packing checklist for returning home

Maternal and Child Health Handbook
My Number health insurance card
🔸Medical and Welfare Benefits Recipient Card
Regular medications
🔸Inhalers for Asthma Attacks
🔸 EpiPen® Neffy® (if prescribed)
🔸 Medicine instructions and medication notebook
🔸Thermometer
Change of clothes
🔸Hats and sun protection items
🔸Drinks you're used to drinking
🔸Contact Information for Your Primary Care Physician
🔸 Information on holiday clinics and emergency medical facilities near your hometown/where you are visiting

🌻 For an enjoyable trip home

When returning to your hometown, multiple unfamiliar conditions combine, such as travel, heat, meals, bedding, and contact with animals.
Even a small change for adults can be a heavy burden for babies or children with allergies.
Please check the following four points before returning home for the holidays.
🔸Preventing Heat Exhaustion and Dehydration
🔸 Do not feed first-time foods while visiting your parents' home
🔸If you have a dust mite allergy, bring a thoroughly washed comforter or rent one.
Understand that if you have a dog or cat allergy, exposure cannot be avoided as long as you remain in the environment where they are kept.
If your child experiences symptoms every year when visiting family, or if you have concerns about how to use their medication, please consult your family doctor before your trip.

[Medical Evidence and Supplementary Materials]

📊 In Japan, anaphylaxis caused by tree nuts is increasing.

In a multicenter retrospective study targeting pediatric food-induced anaphylaxis in Japan, the proportion of walnuts among causative foods increased from 3.2% in 2011 to 26.1% in 2021.
It has also been reported that, among children whose anaphylaxis was caused by walnuts, the proportion who had been diagnosed with a walnut allergy prior to the onset of symptoms was lower than that observed for anaphylaxis caused by other food allergens. [1]
A survey of emergency medical facilities in Aichi Prefecture regarding pediatric anaphylaxis also showed that the proportion of tree nuts among causative foods increased from 6.0% in 2017 to 15.0% in 2019. [2]
Children often have few opportunities to eat nuts during infancy and early childhood, and may try them for the first time only as they get older.
Not trying new foods while visiting your hometown is the most important preventive measure.

🥜 Hard beans and nuts also pose a choking hazard.

硬い豆やナッツ類は、食物アレルギーとは別に、窒息や誤嚥の原因になります。
消費者庁は、5歳以下の子どもには、硬い豆や粒のままのナッツ類を食べさせないよう注意喚起しています。[3]

🧺 洗濯はダニとダニアレルゲンを除去します

ダニ対策では、ダニを死滅させることだけでなく、ダニの死骸やふんに含まれるアレルゲンを寝具から除去する必要があります。
ダニが死滅しても、死骸やふんが寝具に残れば、アレルギー症状の原因になります。
洗濯では、水に浸すこと、洗剤を使用すること、すすぎによって物理的に洗い流すことにより、ダニとダニアレルゲンを減らすことができます。
天日干しでは、すでに寝具に蓄積しているダニアレルゲンを除去できません。帰省先で長期間保管されていた布団は、天日干しではなく、丸洗いが必要です。

🛡️ 防ダニシーツの単独使用では症状改善効果がありません

防ダニシーツや防ダニカバーを単独で使用しても、ぜんそく症状などの改善効果は示されていません。
防ダニシーツだけを使用する方法は、ダニアレルギーの対策にはなりません。
帰省先では、防ダニシーツの購入よりも、丸洗いした布団または適切に洗浄・整備された貸布団の使用を優先してください。

🐶🐱 犬・猫アレルゲンは家全体に広がります

犬や猫のアレルゲンは、唾液、皮脂、フケなどに由来し、非常に細かな粒子として室内に広がります。
アレルゲンは、床、じゅうたん、ソファ、カーテン、寝具、衣服などに付着します。
犬や猫が入らない部屋にも存在し、衣服に付着して、犬や猫を飼っていない建物へ運ばれることもあります。
そのため、犬や猫を別室に移しても、子どもが動物のいない部屋で過ごしても、アレルゲンへの曝露を避けることはできません。

🚪 飼育を続けたまま、曝露のない家庭環境をつくることは困難です

犬猫アレルギーに対して、別室、掃除、空気清浄機、寝室への立ち入り禁止、動物の洗浄などによって、症状を確実に改善する十分なエビデンスはありません。
犬を洗うと、犬の毛に付着している犬アレルゲンは一時的に減少します。
しかし、数日で再び増加するため、犬を洗うだけでは、家庭内での症状を防ぐ対策にはなりません。

🐾 動物がいなくなった後もアレルゲンは残ります

猫が生活していた住宅では、猫がいなくなった後も、室内の猫アレルゲンが十分に低下するまで数か月かかることがあります。
帰省の直前に犬や猫をほかの場所へ移しても、室内に蓄積したアレルゲンへの曝露を防ぐことはできません。

References

[1] Iwashita Y, Kajita N, Yoshida K, et al. Eleven-Year Trends in Walnut-Induced Anaphylaxis in Children in Japan: A Multicenter Retrospective Study. Pediatric Allergy and Immunology. 2025;36:e70243.
[2] Kitamura K, et al. Time Trends of Triggers and Adrenaline Use in Pediatric Anaphylaxis in Aichi, Japan. Allergology International. 2021.
[3] 消費者庁．食品による子どもの窒息・誤嚥事故に注意―硬い豆やナッツ類等は5歳以下の子どもには食べさせないで―．2021．
[4] Arlian LG, Vyszenski-Moher DL, Morgan MS. Mite and Mite Allergen Removal During Machine Washing of Laundry. Journal of Allergy and Clinical Immunology. 2003;111:1269-1273.
[5] Portnoy J, Miller JD, Williams PB, et al. Environmental Assessment and Exposure Control of Dust Mites: A Practice Parameter. Annals of Allergy, Asthma & Immunology. 2013;111:465-507.
[6] Cloutier MM, Baptist AP, Blake KV, et al. 2020 Focused Updates to the Asthma Management Guidelines: A Report from the National Asthma Education and Prevention Program Coordinating Committee Expert Panel Working Group. Journal of Allergy and Clinical Immunology. 2020;146:1217-1270.
[7] Portnoy J, Kennedy K, Sublett J, et al. Environmental Assessment and Exposure Control: A Practice Parameter—Furry Animals. Annals of Allergy, Asthma & Immunology. 2012;108:223.e1-223.e15.
[8] Hodson T, Custovic A, Simpson A, Chapman M, Woodcock A, Green R. Washing the Dog Reduces Dog Allergen Levels, but the Dog Needs to Be Washed Twice a Week. Journal of Allergy and Clinical Immunology. 1999;103:581-585.